Alot of those reviews seem like they are looking at the older sound blaster line and not the newest line and based the facts off that, because sound cards like the sound blaster Z, ZXR and the Titanium HD PCI-E are actually very good sound cards and compare very good to the Xonar D2X, Xonar STX and Xonar ST in re guards to audio performance. As for game performances if you mean hardware acceleration then that is moot, today cpus are much faster and are able to handle doing the work for audio, it be something different if you was on a older single core cpu or a older dual core cpu where you would notice it. But on todays cpu you wont notice it and it moot to get a sound card for fps improvements that wont even be 1fps. Graphics cards is where you would get more fps at any way. I have own wide ranges of Asus Xonar and creative cards and I had none of those issues with game performances that people are mention in the reviews.
If Asus cards are the only cards in your location then a Asus Xonar STX if you have a free PCI-E 1x slot or PCI-E4x slot, Don't place it in a long 16x slot as you will hear bus sounds from the graphics card. If you have a spare PCI then Asus Xonar ST, both ST and STX has a headphone amp that will handle 250ohm headphones. The only reason I mentioned the creative cards because they tend to be what people go for when they are gonna be gaming, For the creative features that not on any C-media based card. If you use Virtual headphone then the Asus Xonar will have dobly headphone and when it is config correctly, with the speakers settings in windows and games set to 5.1 with the asus console panel set to 5.1 input and headphone output. Dolby Headphone can work very well. Of course turn it off and revert to stereo for music. Z series has SBX surround headphone option which work the same way and Z series including the basic Z can handle 250ohm headphones as well and the ZXR has the same headphone amp that the ST/X and STX2 has. As well having op-amp sockets for changing op-amps. Which change the sound signature of the sound cards.
The U7 and the DG/X has the same headphone amp it just the U7 is a external DG/X. With the DX you will need to get a external headphone amp as the DX it self wont be able to drive 250ohm headphones. The DG/X U7 will be able to handle DT770 pro-80 as they are easier to drive. But not the 250ohm as the DG/X wont be driving them completely. You can still use a DG/X but in the long run the 250ohm models wont shine til a stronger headphone amp is plugged into them.
Also I suggest if you can go some where, where you can listen to those headphones that you are looking at and pick the one that you like, but make sure their listening stations are up to par so you can hear what they sound like exactly and not half driven.
Edited by genclaymore - 6/24/14 at 6:13am